Efficacy and safety of tixagevimab‐cilgavimab versus SARS‐CoV‐2 breakthrough infection in the hematological conditions

Background Managing SARS‐CoV‐2 infection in frail and immunosuppressed patients still represents an open challenge, but, starting from the phase 3 PROVENT study, prophylaxis with tixagevimab‐cilgavimab has improved the approach in this category of patients, guaranteeing a better outcome and inferior mortality. Real‐life data in a heterogeneous cohort are few. Methods The aim of this study is to evaluate the benefit of prophylaxis with tixagevimab‐cilgavimab in a cohort of 202 patients affected by different hematological diseases (lymphoproliferative, myeloproliferative, autoimmune, patients recently receiving a bone marrow transplant), active (with ongoing treatment), or in watch‐and‐wait strategy, followed in our center, during a median follow‐up of 249 (45‐325) days. Results An incidence of 44 breakthrough infections (21.8%) is reported, with no treatment‐related adverse effects. Age ≥70 years, ongoing treatment (above all with monoclonal antibodies), baseline lymphoproliferative disorders, and prior virus exposure are identified as risk factors related to subsequent infection (p